The invention relates to a device for inscribing and/or reading a magneto-optical information carrier, the device comprising a frame with a turntable which is rotatable about an axis of rotation for supporting the information carrier; an optical unit arranged to be movable transversely of the axis of rotation and comprising a focusing optics for concentrating a radiation beam to form at least one radiation spot in a focusing plane, and an actuator for moving the focusing optics at least in a direction parallel to the axis of rotation; and a magnetic unit which, viewed in the direction of the axis of rotation, is arranged opposite to and is spaced from the optical unit, for generating a magnetic field which extends into the focusing plane. The magnetic unit is secured to a displacement body which is movable in a direction transverse to the axis of rotation.
Such a device is known from German Offenlegungsschrift DE 37 23 134. The prior-art device for magneto-optically inscribing a magneto-optical disc comprises a housing having a cover which can be opened and closed to insert or remove a magneto-optical disc. During operation the magneto-optical disc loaded into the housing is held on a turntable by a disc-pressure member and is rotated by a drive motor. The drive motor is secured to a frame accommodated in the housing. The housing further accommodates a slide which is movable over rectilinear guide means of the frame in a radial direction relative to the axis of rotation of the turntable. The slide is constructed as a tilted U-shaped part having two mutually parallel limbs which extend in radial directions relative to the turntable. One of the limbs carries an objective for concentrating a radiation beam to form a radiation spot and the other limb carries a permanent magnet for producing a magnetic bias field. The objective and the magnet are arranged opposite one another and are situated each at one side of the supporting surface of the turntable.
The information carrier to be used for magneto-optical recording is provided with a thin film of a ferromagnetic or a ferromagnetic material having a direction of easy magnetisation perpendicular to the surface of the thin film. During recording it is necessary that the thin film is heated to a temperature above the Curie temperature, or in the case of ferromagnetic materials to a temperature above the so-called compensation point. When the known device is used the magneto-optic disc is inscribed by applying a magnetic bias field by means of the permanent magnet and the thin film is heated by means of a pulsating laser beam.